Construction of buildings, particularly high-rise buildings and apartments, requires the involvement of multiple trades people.
People who install dual unit air conditioners usually need to be present on site a number of times. Generally, on their first visit, they install the necessary piping into the cavities between wall studs in the walls and in the roof. The piping is then left, usually hanging and exposed from a wall stud because the installers need to wait for other trades people (e.g. plasterers, builders and painters) to finish their parts of the construction process. Often, the exposed pipes can be damaged by the builders or other trades people.
Once the wall boards (which are typically formed of plaster) are installed on the wall studs, the air conditioner installer then returns to complete the installation process. They must first determine the ideal location for the air conditioner according to the location of the piping and the wall studs. Locating the wall studs is usually relatively straightforward—the installer may, for example, use a stud finder or tap on the wall boards with their knuckles until the position of the wall studs has been ascertained. However, locating the piping can often require guesswork as it will often have been completely covered by the wall boards. This may lead to an installer scoring or damaging the wall boards a numbers of times before the piping is located.